This invention relates to a method for the production of fabrics with a rib structure, in particular of false boucle fabrics, whereby on a weaving machine weft threads are inwoven by a series of warp threads so that a fabric is formed with sets of at least two weft threads running one above the other, and pattern warp threads which are alternately interlaced in the fabric and are rib-formingly passed around a set of weft threads.
This invention also relates to fabrics with a rib structure which are manufactured according to such a method, in particular false boucle fabrics, comprising weft threads which are inwoven by a series of warp threads, sets of at least two weft threads running one above the other, and pattern warp threads which are alternately interlaced in the fabric and run rib-formingly above a set of weft threads.
A fabric with a rib structure which approximates the appearance of a loop pile fabric or boucle fabric, is called a false boucle fabric.
According to a known weaving method for manufacturing a false boucle fabric, which has the above mentioned characteristics, tension warp threads are provided and in each weft insertion cycle on the weaving machine two weft threads are simultaneously inserted one above the other. In successive insertion cycles the two weft threads are in relation to the tension warp threads alternately inserted along the upper side of the fabric and along the back of the fabric.
Two pattern warp threads with a different color are provided in order to be able to make a design or a pattern visible with the two colors along the upper side of the fabric.
In several systems of warp threads a first pattern warp thread is alternately brought above the two weft threads located along the upper side of the fabric and interlaced between the two weft threads located along the back of the fabric, in order to implement a rib structure on the upper side of the fabric and to form the design or pattern, while a second pattern warp thread is alternately interlaced between the two weft threads located along the upper side of the fabric and is brought below the two weft threads located along the back of the fabric. The color of the second pattern warp thread is then visible on the back of the fabric. The second pattern warp thread forms a rib structure on the back of the fabric. With these fabrics the weft threads are inwoven by the pattern warp threads. With each insertion cycle a rib line is produced (alternately along the upper side and along the back of the fabric).
Both the upper side and the back of the fabric have a rib structure. On the back of the fabric a type of negative (with swapped colors) is obtained of the two-colored design which is visible on the upper side of the fabric.
Manufacturing fabrics with a rib structure on a weaving machine can only be effected according to the known methods at a moderate productivity.
The purpose of this invention is to provide a method for manufacturing such fabrics, according to which work can be effected on a weaving machine with a considerably higher productivity.
This purpose is achieved because of the fact that according to this invention with a method having the characteristics mentioned in the first paragraph of this specification two series of warp threads are provided for weaving a respective fabric on a weaving machine, and in each insertion cycle of a number of successive insertion cycles, in each case at least three weft threads are inserted one above the other between the warp threads, so that in each case a set of weft threads running one above the other is inwoven by the warp threads of one of the two series, and at least one weft thread is inwoven by the warp threads of the other series, so that two fabrics with a rib structure are woven.
According to the method according to this invention two fabrics can be woven simultaneously on a weaving machine.
Utilizing this method in place of the known methods therefore doubles the productivity.
According to this method in each insertion cycle at least one thicker weft thread is preferably inserted and so inwoven that it is part of a set of weft threads running one above the other.
The thicker weft threads ensure that the sets of weft threads running one above the other take up a greater height in the fabric. Because of this ribs are obtained with a somewhat greater height, which produces a fabric with a more pronounced rib structure.
By utilizing the method according to this invention a number of tension warp threads are preferably provided in each fabric, the sets of weft threads running one above the other are inwoven in the top of the fabric in relation to the tension warp threads, and the pattern warp threads are interlaced in the fabric below weft threads which are inwoven along the back of the fabric in relation to the tension warp threads. Because of this very clearly perceptible ribs are obtained in the fabrics.
According to another preferred method according to this invention whereby in each insertion cycle a thicker weft thread is inserted, in each fabric a number of tension warp threads are provided, of each set of weft threads only the aforesaid thicker weft thread is inwoven along the upper side of the fabric in relation to the tension warp threads, and the pattern warp threads are interlaced in each fabric below weft threads which are inwoven along the top of the fabric in relation to the tension warp threads.
This method makes it possible to weave fabrics with a rib structure with a minimum pattern warp thread consumption and a maximum productivity.
Preferably the method is so implemented that the warp threads of both series alternately inweave a set of weft threads running one above the other. Thus per two successive insertion cycles a rib is obtained on the top of both fabrics.
In the successive insertion cycles in each case for example three weft threads can be inserted simultaneously one above the other.
The method according to this invention is very efficient if the two fabrics are woven one above the other with the top directed toward each other, whereby the weft thread inserted on the top insertion level is in each case inwoven by warp threads of the top fabric, the weft thread inserted on the bottom insertion level is in each case inwoven by warp threads of the lower fabric, and around the weft threads which are inserted on the middle insertion level in successive insertion cycles alternately a pattern warp thread of the top fabric and a pattern warp thread of the bottom fabric is passed around.
In order to form a design or pattern on the upper side of a fabric pattern warp threads must be visible in one location in the fabric and not in the other location. A pattern warp thread which may not be visible in a specific location along the top of the fabric is then inwoven in the fabric. These (parts of) pattern warp threads are called dead or non-pattern-forming (parts of) pattern warp threads.
According to this invention non-pattern-forming pattern warp threads, or parts thereof, preferably, married to the tension warp threads, are inwoven stretched in the fabric. Thus for these non-pattern-forming (parts of) pattern warp threads an extremely low thread consumption is achieved.
The non-pattern-forming pattern warp threads or parts thereof, can also be alternately undulatingly inwoven in the fabric running between two weft threads of a set located one above the other and below a weft thread. In that manner a greater rib height is obtained and the rib structure in the fabrics becomes clearer.
According to a greatly preferred method according to the invention backing weft threads are inwoven by binding warp threads so that two backing fabrics are formed, work is so performed that each set of weft threads comprises a backing weft thread and a pattern weft thread not inwoven in this backing fabric, and pattern warp threads are alternately passed around a pattern weft thread and interlaced in a backing fabric by a backing weft thread located between two sets of weft threads.
It is clear that both the above specification and the methods described in the claims and the fabrics with a rib structure, in particular the false boucle fabrics, which are manufactured according to one of these methods, are covered by the protection claimed by this patent application.
In such a fabric that is particularly preferred, backing weft threads are inwoven by binding warp threads so that a backing fabric is formed, each set of weft threads located one above the other comprises a backing warp thread and a pattern weft thread extending there above and not inwoven in the backing fabric, pattern warp threads are alternately passed around a pattern weft thread and interlaced in the backing fabric by a backing weft thread located between two sets of weft threads.
By utilizing the above described method for the production of fabrics with a rib structure, and by afterward removing at least one of the weft threads of each set, fabrics are obtained in which the pattern warp threads (which initially ran rib-formingly above the sets of weft threads) now form loops on the upper side of the fabrics. Thus on the basis of the inventive idea of the above specified method a method can also be provided for manufacturing loop pile fabrics (boucle fabrics) with a high productivity.
Methods exist for manufacturing loop pile fabrics, whereby on a weaving machine two series of warp threads are provided, and weft threads are inserted between the warp threads so that a top and a bottom fabric are woven with loop warp threads which are alternately interlaced in the fabric and are loop-formingly passed around a loop weft thread, and whereby the loop weft threads are subsequently removed so that two loop pile fabrics are obtained simultaneous.
According to a number of known methods the weft insertion capacity of the weaving machines is not however utilized to a maximum. According to other known methods work is performed with a rather low productivity.
In order to remedy these and other disadvantages of the known methods, according to the method according to this invention two fabrics are manufactured according to one of the methods described above (and in claims 1 through 9), whereby at least one weft thread of each set of weft threads running one above the other functions as loop weft thread and is removed so that the pattern warp threads running above these sets form loops.
It is preferably the top weft thread of each set (the pattern weft thread) which is removed.
Preferably backing weft threads are inwoven by binding warp threads so that two backing fabrics are formed, work is so performed that sets of at least two weft threads running one above the other comprise a backing weft thread and a loop weft thread not inwoven in this backing fabric, and loop warp threads are alternately passed around a loop weft thread and interlaced in a backing fabric by a backing weft thread located between two sets of weft threads.
According to the most efficient method all loop weft threads are inserted on one and the same middle insertion level, a top series of loop-forming elements (e.g. lancets) are provided between the insertion level of the loop weft threads and the insertion level of the weft threads inserted there above, and a bottom series of loop-forming elements is provided between the insertion level of the loop weft threads and the insertion level of the weft threads inserted there under.